/Engine/Source/Runtime/Engine/Classes/Engine/LocalPlayer.h
This function will give you a point in Pixel Space from a World Space position
False if there is no viewport, or if the box is behind the camera completely
static bool GetPixelPoint ( const [FSceneViewProjectionData](API\Runtime\Engine\FSceneViewProjectionData) & ProjectionData, const FVector & InPoint, FVector2D & OutPoint, const FVector2f * OptionalAllotedSize )